top of page
  • hbanziger

F - 20 : Montreux Convention - More than just a Piece of Paper

Updated: Jul 26, 2022

One of 50 Russian Warships which sailed in 1921 through the Bosporus to the Mediterranean

Standing on the Four Seasons’ terrace that overlooks the Bosporus, you can watch large freighters passing by. More than 100 commercial vessels use the Turkish Straits every day. Makes 4 big ships every hour. The Bosporus is open 24/7. In 2021, the number of vessels amounted to 38’551, ferries and local boats not included. The number increased almost nine-fold since 1938 from “only” 4’500. Also, the ships then had 25 times less cargo volume than today. Amongst the 38’551 ships last year were 50 Russian warships going south and 43 returning to the Black Sea.

The Bosporus from North to South. It is 31km long

The Turkish Straits, Bosporus to the North and Dardanelles to the South, are governed by the Montreux Convention from 1936. The Straits are international waters for commercial shipping. Turkey has the right to close them for naval traffic for nation’s at war though. The Turkish Government invoked the respective treaty clause in February after Russia invaded the Ukraine. A few Russian warships were allowed to return to their home base but since their passage, the Straits remain closed. The clause does not apply for Belgian, Italian, Greek and Polish warships taking part in the annual NATO exercise “Breeze” with Turkey, Romania and Bulgaria this July. These countries are not at war.

One of the Frigates participating in Exercise "Breeze 2022" from a French Patrol Aircraft

The Turkish Straits were always of strategic importance. Last year, 20% of the cargo going south were fossil fuels. 2’800 years ago, it was wheat from the shores of the Sea of Azov for Athens. During Mongol times, Bosporus and Dardanelles were Europe’s link to the northern end of the silk-road. It was also Imperial Russia’s only warm exit to the sea. The Straits do not freeze over during winter. For centuries, Russia tried to win control over them. The Soviet Union continued these efforts after 1945. It is one of the reasons why Turkey joined NATO.

Traffic Density Map - The Number of Ships decreased from from 55k to 38k but the Gross Tonnage increased from 420 million tons to 630 million since 2006

The “Question of the Straits” – as the British Foreign Office so eloquently put in the 19th century – was a non-brainer during antiquity. In the absence of long-distance weapons, a big fleet was necessary to control both Bosporus and Dardanelles. The Persians, Athenians, Macedonians, the Romans and Byzantines all had large fleets with hundreds of vessels. The only exceptions happened in 674 - 678 AD, when the Califs established their own fleet base in the Sea of Marmara to take Constantinople. But they failed. They had no defence against the Byzantine's Greek Fire.

Arab Attack on Constantinople in 674 AD - the painting is from the 19th Century

But the time of big fleets protecting the Straits was over when Constantinople was sacked in 1204 by the 4thCrusade. Venice and Genoa became the Masters of the Straits until 1453. Their fleets of 30 – 40 vessels each were tiny but in the absence of opposition sufficient to control the waterways. Both could conduct their lucrative activities with the Mongols undisturbed and make a killing from trading slaves and Chinese luxury goods. The Genovese and Venetians labeled the blond girls and boys the Mongols sold as pagans to circumvent the Papal rule that Christians must not be enslaved. Just remember when admiring next time one of their – indeed – beautiful palaces! Built with slavery money.

Construction of a Warehouse in the Genovese Colony in Trebizond. The Picture was painted by Luca Cambiasi in 1571

The rising Ottoman Empire put an end to this “Italian” business. Open minded and innovative, the Ottomans took an interest in early gunnery and hired experts from Europe. When the Turkish Sultan Mehmet the Conqueror decided to attack Constantinople, he knew he had to close the Straits to prevent aid from getting to the besieged city. In 1452, he built the Rumeli Castle, installed a gun battery and asked every passing ship to pay a levy. Of course, Italian bravery did not allow the Venetians to stop. To their peril, they underestimated the skills of Ottoman gunnery. Their fragile galley was hit and sunk, the crew beheaded and the captain impaled and exhibited on the walls as a warning. Firepower had closed the straits. For the next 300 years, the Ottoman Empire expanded and the Black Sea and the Straits became domestic Turkish waters.

The Rumeli Fortress north of Istanbul with its central Gun Tower

This state of affairs was shattered when Turkey badly lost the war with Russia in 1774. The army was defeated by General Suvorov and 22 Turkish warships sunk by Admiral Orlov, who had sailed his Baltic Fleet around Europe. The consequences of the ensuing peace were far reaching. Imperial Russia gained the Azov ports, the land between Dnieper and Bug and Crimea as a client state. It was now a coastal state on the Black Sea which became international waters. Logically, Russia demanded free passage through the Straits to the Mediterranean. Under the peace treaty of 1774, it also became the protector of Orthodox Christianity and henceforth meddled in the internal affairs of Romania, Serbia, Bulgaria and Greece. The consequences were 150 years of violent turmoil in the Balkans.

In the Battle of Cesme Admiral Orlov destroyed 22 Turkish Vessels with his Fireships

But the international situation was not the only change. Technology had progressed and firepower alone could not close the Straits any longer. The battle ships of the line became too resilient to be stopped by guns alone. A British Fleet fought its way up the Dardanelles and reached Constantinople in 1807. But sea mines changed the game again and when a French-British Fleet tried to force the Dardanelles in 1915, it failed. Three battleships ended at the bottom of the sea.

In 1807, the British Admiral Duckworth forced the Dardanelles and reached Constantinople. His Ships of the Line were sturdy enough to withstand the fire from the Turkish Forts

All the while, the strategic importance of the Straits increased. The industrialization of Russia in the 19thcentury connected its ports to the world. Russian grain, coal and steel were shipped through the Straits. In one of the secret protocols leading to the 1st World War, France and England promised to cede the Straits to Russia. But Russia descended into the chaos of the Russian Revolution in 1917 and the plan was never executed. A British-French-Italian Expeditionary Force occupied the Straits though from 1918 to 1923 when the peace treaty of Lausanne was signed. In this Treaty the Straits were declared international waters. Turkey had lost control over the straits.

The Area secretly ceded to Russia in the secret wartime agreements before 1914 in yellow

Time stood not still though and the power balance in the Mediterranean shifted again. In Italy, Mussolini came to power n 1922 and publicly dreamed of his Mare Nostrum. By 1935 Italy had built a Navy with 4 battleships, 7 heavy cruisers, 14 light cruisers, 120 destroyers and 119 submarines. It was as modern as the British Fleet.

Modern Italian Destroyers in 1935 in the Harbour of La Maddalena in Sardinia

People started to take notice. The Turkish President Ataturk was concerned that France and England, the signatory powers of the Lausanne Treaty did not have the capacity to defend the Straits and wanted to renegotiate the treaty. A compromise was found with the Convention of Montreux. For commercial shipping the Straits would always be open. But during times of war, Turkey was allowed to close the Straits to warships and defend them by its own means, meaning forts and sea mines. Turkey was also allowed to refuse passage to commercial ships of nations with which it is at war. Non-Black Sea Powers have to notify Turkey 15 days in advance if they want to send warships through the Straits, Black Sea Powers 8 days. The total number of warships per passage is limited to 9. There are also restrictions on the total tonnage.

The sunk Moskva Missile Cruiser could be replaced by its Sister Ships Marshal Ustinov, which serves in the Northern Fleet, or the Varyag, part of the Pacific Fleet, were it not for the Montreux Convention

Through their entire history, passage through the Straits was always controlled by the regional power if it had the means to do so. Only from 1923 – 1936 was a completely liberal regime in place. But this was designed under the illusion that the First World War was the war to end all wars. Sadly, it did not turn out this way. The Montreux Convention may look like an old piece of paper. But it prevents Russia from reinforcing its Black Sea fleet once the war against in the Ukraine started. Am sure the Russian General Staff would love to replace the Moskva after it was sunk. There are sister ships in the Northern and Pacific Fleet. The Montreux Convention makes this impossible.

32 views0 comments

Recent Posts

See All


bottom of page